For over forty years, the performance of effective chest compressions during CPR has been recognized as a key determinant in a victim's chance of survival from cardiac arrest. However, it is known that the proper administration of CPR is physically demanding, requiring the quick, consistent application of intense forces. Consequently, anatomical strain and physical fatigue are prevalent problems plaguing rescuers performing CPR. Recent changes in protocol have made CPR even more rigorous: a recommended compression to breaths ratio of 15:2 has been increased to 30:2.
A 2002 study concluded that rescuer fatigue adversely affects the quality of chest compressions when performed without interruption over a three minute period and that this effect may be more pronounced in females due to their smaller stature. Naturally, this conclusion may be extended to any healthy individual with smaller stature or lack of muscle tissue and bone structure in the wrist area. (Ashton et al., Effect of rescuer fatigue on performance of continuous external chest compressions over 3 min, Resuscitation 55(2002), 151-155). The study found that the rate of satisfactory compressions dropped from 82 to 52 over a three minute period. The study also indicated that optimally performed CPR provides only one third of normal cardiac output and so even a modest deterioration in performance may have a clinically significant adverse result.
Rescuer exhaustion is not the only factor preventing the effective performance of CPR; a significant portion of the population is unable to properly administer chest compressions due to wrist or hand diseases and disorders. Hand and wrist problems are common: a 2007 paper on hand and wrist ailments indicated that the incidence of new cases of wrist problems in the general population was 4.6/1000/yr and that of hand and finger ailments was 7.8/1000/yr (Hand and wrist problems in general practice—patient characteristics and factors related to symptom severity, Rheumatology 2007; 46:1723-1728). It was also indicated that 12.5% of the sampled population had some form of wrist or hand problem. Beyond injuries and generally weak bone structure, many common diseases can lead to a destabilizing of the wrist joint. For example, a 1999 study in the United States found that the prevalence of carpal tunnel syndrome is 50/1000 with an incidence of 1-3/1000/yr (Atroshi I, Gummesson C, Johnsson R, et al: Prevalence of carpal tunnel syndrome in a general population. JAMA Jul. 14, 1999; 282(2): 153-8). Carpal tunnel syndrome (CTS) is a collection of characteristic symptoms and signs that occurs following entrapment of the median nerve within the carpal tunnel. Usual symptoms include numbness and paresthesias and may be accompanied by objective changes in sensation and strength of median-innervated structures in the hand. Such a common disorder may preclude otherwise willing bystanders from being able to effectively perform CPR. Other wrist-related ailments such as arthritis and tendonitis are also common in the general population and especially among the growing population of the elderly who are most likely to be nearby when CPR is required.
Previously, certain cardiopulmonary resuscitation (CPR) assist and aid devices have been invented that instruct the user on the proper administration of CPR. One such device, disclosed in U.S. Pat. No. 5,239,988 to Swanson et al., is in the form of a wristwatch that includes audible signals that are emitted from a beeper at a rate dependent on which of a set of push buttons is pressed. This device is used in the timing of external heart massage or CPR. Although worn on the wrist, this device provides no support to the wrist, hand or arm and is simply designed to provide user instructions; feedback based on the quality of the rescuer's CPR is not provided by this device.
A second device, disclosed in U.S. Pat. No. 7,122,014 to Palazzolo et al., is a compression monitor that consists of accelerometers and tilt sensors to measure compression depth during the administration of CPR. In one embodiment, the accelerometer based device can be placed on the wrist or hand. Unlike the device disclosed in U.S. Pat. No. 5,239,988, this device provides feedback to the rescuer on parameters such as compression depth and rate. However, the device of Palazzalo et al. does not include any form of wrist, hand or arm support or guard to protect the affected joints and limbs of the rescuer during CPR.
Other rescue administration devices that may be worn on the wrist include those disclosed in U.S. Pat. Nos. 5,088,037 and 7,245,964. However, these devices are worn on the wrist only for convenience, and are not intended to provide any support or strengthening to the wrist.
Despite an abundance of CPR assist, monitoring and aid devices, there has yet to be a device designed to alleviate the symptoms and pains associated with joint discomfort and fatigue during the administration of CPR.